What micron size do we need? Water filtration

When specifying filtration for an industrial water system, one of the first questions is often: What micron size do we need? It is an important question, but it is only the beginning. A screen designed to filter at 50 microns, for example, may sound appropriate on paper. However, reliable industrial filtration depends on more than the size of the particles being removed. The characteristics of those particles, water flow, screen geometry, cleaning method, operating environment and required service life will influence performance.

At ActionLaser, we manufacture precision stainless steel filtration screens for applications where these factors need to work together. Understanding the complete application allows a screen to be engineered for the filtration task rather than manufactured to a nominated micron number.

Industrial water often contains many different types of suspended material. Sand, soil, silt, and fine mineral particles are commonly found in mining. Industrial wastewater generally contains sludge or solids generated during production. Closed-circuit cooling systems can accumulate fine contaminants originating from equipment, coatings, resins and other materials within the system.

Two applications requiring filtration at a similar micron level may behave very differently.

Particle characteristics, concentration and the volume of material reaching the screen need to be considered. The objective is to achieve the required level of separation while maintaining sufficient water flow and avoiding unnecessary process interruptions.

Industrial filtration covers an enormous spectrum. Coarse filtration can remove relatively large solids, while membrane technologies such as ultrafiltration, nanofiltration and reverse osmosis operate at extremely fine levels. ActionLaser’s capabilities span approximately 25 to 400 microns, with particular strength in the sub-100-micron range. This makes precision laser-drilled screens well-suited to applications involving fine suspended solids, including silt, sludge, and sandy soils.

In some water treatment systems, this is the required filtration stage. In others, mechanical filtration provides valuable pre-filtration before water reaches finer downstream treatment technologies.

A filtration screen is not just a flat piece of material containing holes of a particular size. The geometry of each aperture influences how effectively liquids and particles move through the screen. ActionLaser can produce screens with tapered apertures, in which the precision opening on the working face increases towards the non-working face. Once material passes through the controlled opening, the expanding geometry helps it evacuate through the screen rather than becoming trapped within the aperture.

This can help reduce blockage and support more consistent filtration performance. Laser drilling provides highly controlled aperture dimensions, allowing screens to be engineered around the requirements of the filtration system.

Every filtration system captures material, so what happens to that material next is critical. If accumulated solids continually block the screen, flow decreases, and the system will require frequent intervention. Effective screen cleaning needs to be considered during the design process rather than as an afterthought.

Depending on the application, filtration screens can be incorporated into systems using backflushing, wiper arms, washing or clean-in-place processes. Other systems maintain solids in suspension before removing them through suction or positive-pressure discharge. The appropriate method depends on the contaminants, equipment and operating conditions.

Closed-circuit cooling water provides a useful example of how filtration requirements extend beyond micron size. In power-generation applications, demineralised water continuously circulates through cooling infrastructure. While the water begins relatively clean, particles can enter the water stream from internal surfaces, specialist coatings, resins and metallic components.

Precision screens can continuously capture these contaminants and be cleaned through backflushing. For permanent industrial installations, durability becomes important. A screen that can be effectively cleaned and reused over an extended operating life provides a very different value from filtration media that require frequent replacement.

Mining water presents another demanding environment. Suspended soil, sand, silt and mineral particles create challenging conditions for filtration equipment, particularly where water is being recovered for reuse. Wastewater applications can introduce different combinations of sludge and suspended solids.

In both cases, the required micron rating is only one consideration. Screen strength, open area, flow, aperture accuracy, contaminant loading, and cleaning requirements all contribute to the filtration system’s reliability.

There is rarely a universal industrial filtration screen. The best solution starts by understanding what the customer is trying to achieve: what needs to be removed, how much water must pass through the screen, how the captured material behaves and how the system will be cleaned.

ActionLaser combines precision laser drilling with engineering expertise to manufacture filtration screens around these requirements. Micron size provides an essential specification. But when filtration is part of a critical industrial process, reliable performance comes from getting the entire screen design right.

Contact us today to learn more about how we work with you to create solutions that deliver long-term results.